Whatever you choose, consider this; light flies better. Always. Heavy warbirds, especially nose-heavy warbirds are no fun to fly. When the wing loading creeps up over 35, be careful. Don't forget to add in the weight of the fuel in your calculations. As a side note, I've been balancing my warbirds with a half tank of fuel, since I find I've been landing with that amount after 7-9 minutes. Just a thought. I realize that's contrary to normal procedure, but jeez, it works great and provides a good balance point. Balance with the wheels down, by the way.
I think modern electric retracts are the best (light, easy install, dependable), but any setup is OK if done correctly. I've had both the H9 and Top Flite P-47s, they both fly well. My H9 had an OS91 FX with a Pitts muffler and flew very well. Vertical was fantastic. I never use more than what the design calls for in the power department.